Latch assembly for service pin of machine

ABSTRACT

A latch assembly for a service pin of a machine includes a housing, a first member, and a second member. The housing is configured for rotatably receiving the service pin. Further, the housing defines a sliding structure for axial movement of the service pin at a rotational position of the service pin. The first member is pivotably attached to the housing and is adapted to selectively prevent rotation of the service pin. The second member of latch assembly is configured to be slidably attached to the housing and movable to a bottom position to retain the first member.

TECHNICAL FIELD

The present disclosure relates to the field of lift arm for machines. In particular, the present disclosure relates to a latch assembly for holding a service pin with a lift arm of a machine.

BACKGROUND

Machines such as earth moving machines, construction machines, mining machines or underground mining machines for example underground mining loaders or a load haul dump machine generally include a bucket to carry or load the material. The bucket is attached to one end of a lift arm of the loader and raised by moving the lift arm using fluid cylinders. The other end of the lift arm is attached to the frame of the machine.

For desired operational performance, regular servicing or maintenance of the machine is performed. For inspection or maintenance of the lift arm, fluid cylinders associated with lift arm, bucket or other components, the lift arms are generally maintained in a raised position. One way of holding the lift arm in the raised position is to extend the lift arm cylinder by operating a lever in an operator cabin and hold the lever in that position. However, the lift arm may come down due to fluid leakage in the cylinders or inadvertent movement of the lever by a person.

The other way of maintaining the lift arm in the raised position is to provide a pin on the lift arm. The pin is movable to an operational position for engaging a stationary frame. When not in use, the pin is moved to a storage position and locked onto the lift arm using a locking device. The locking and unlocking of the pin may be performed by a tool. Also, the removed locking device may get lost which is not desirable. U.S. Pat. No. 7,712,235 discloses a lock device that prevents a boom of a backhoe work machine from being rotated downward by its weight.

SUMMARY OF THE INVENTION

According to an aspect, a latch assembly for a service pin of a machine is disclosed. The latch assembly includes a housing for rotatably receiving the service pin. Further, the housing defines a sliding structure for axial movement of the service pin at a rotational position of the service pin. The latch assembly further includes a first member pivotably attached to the housing and is adapted to selectively prevent rotation of the service pin. A second member of latch assembly is configured to be slidably attached to the housing and movable to a bottom position to retain the first member.

According to another aspect, a service pin assembly for a machine is disclosed. The service pin assembly includes a service pin, a housing, a first member, and a second member. The housing is configured for rotatably receiving the service pin. The housing includes a sliding structure for axial movement of the service pin at a rotational position of the service pin. The first member is pivotably attached to the housing and is adapted to selectively prevent rotation of the service pin. The second member is slidably attached to the housing and movable to a bottom position to retain the first member.

In yet another aspect, a machine is disclosed. The machine includes a lift arm, a service pin, a housing, a first member, and a second member. The service pin is configured for insertion in the lift arm. The housing is configured for rotatably receiving the service pin. The housing includes a sliding structure for axial movement of the service pin at a rotational position of the service pin. The first member is pivotably attached to the housing and is adapted to selectively prevent rotation of the service pin. The second member is slidably attached to the housing and movable to a bottom position to retain the first member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of a machine in accordance with an embodiment.

FIG. 2 illustrates a top view of a lift arm having a service pin assembly in accordance with an embodiment.

FIG. 3 illustrates an enlarged view of the service pin assembly depicting a locked position of a service pin in according with an embodiment.

FIG. 4 illustrates an exploded view of the service pin assembly in accordance with an embodiment.

FIG. 5 illustrates the service pin assembly showing position of a latch assembly in accordance with an embodiment.

FIG. 6 illustrates the service pin assembly showing position of the latch assembly in accordance with an embodiment.

FIG. 7 illustrates the service pin assembly showing position of the latch assembly in accordance with an embodiment.

FIG. 8 illustrates the service pin assembly showing position of the latch assembly and the service pin in accordance with an embodiment.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary machine 100 that may incorporate a service pin assembly 118 (shown in FIG. 2). The machine 100 may be configured to perform work associated with a particular industry such as, for example, underground mining, open pit mining, construction etc. For example, the machine 100 may be an underground mining loader (shown in FIG. 1), a load haul dump loader, a wheel loader, a skid steer loader, or any other machine.

As shown in FIG. 1, the machine 100 may generally include a frame 102 which supports traction devices 104, a cab 106, and a power source 108, such as a hydrostatic drive or an engine, and the like. The machine 100 may further include one or more lift arms 110 that are movably coupled to the frame 102 at one end. An implement such as bucket 112 is pivotally attached to working end of the lift arms 110. The bucket 112 may be attached to the lift arms 110 by any suitable coupling means such as a coupler, pin, latches or any other mechanism generally known in the art.

The machine 100 may also be provided with one or more lift arm actuators 116 that operatively couples the lift arms 110 to the frame 102. The lift arm actuators 116 are extended or retracted to raise or lower the lift arms 110. Further, the cab 106 may generally house an operator interface 120 through which an operator may be able to operate any one or more of the traction devices 104, the power source 108, the lift arms 110, the implement 112, and the like.

As shown in FIG. 2, the lift arm 110 includes the service pin assembly 118. The service pin assembly 118 may be mounted at any location of the lift arm 110. The service pin assembly 118 may be mounted on an inner plate 114 of the lift arm 110. The service pin assembly 118 may be mounted proximate to an end 122 of the lift arm 110.

Referring to FIG. 3 and FIG. 4, the service pin assembly 118 includes a latch assembly 124 and a service pin 126. The service pin 126 is configured for insertion in the lift arm 110. The service pin 126 may include a cylindrical structure 128 and an arm 130. The arm 130 may include a groove 134. The arm 130 may extend perpendicular to a longitudinal axis 132 of the cylindrical structure 128. The service pin 126 is retained with the lift arm 110 in a disengaged position by the latch assembly 124 (shown in FIG. 3). In the disengaged position, the service pin 126 is retained with the lift arm 110 by locking the service pin 126 with the lift arm 110 by using the latch assembly 124. In an engaged position, the service pin 126 is unlocked from the latch assembly 124 and rotated and axially moved and inserted in the lift arm 110 to engage another structure such as a stationary frame. The latch assembly 124 when engaged with the service pin 126 prevents the rotational and axial movement of the service pin 126.

The latch assembly 124 includes a housing 136, a first member 138, and a second member 140. The housing 136 is configured to receive the rotatable service pin 126 by permitting axial movement of service pin 126 at a specified angle of rotation. The housing 136 is configured to restrict the axial movement of the service pin 126 unless the service pin 126 is rotated to the specified angle of rotation. The first member 138 and the second member 140 are mounted on the housing 136 and when engaged with the service pin 126 prevent a rotational movement of the service pin 126 in the housing 136. In an embodiment, the housing 136 may include a cylindrical portion 142 defining a sliding structure 144, a first end 146, a second end 148, and a plate portion 150. The cylindrical portion 142 is a hollow portion and may enclose the cylindrical structure 128 of the service pin 126 such that the arm 130 remains outside the cylindrical portion 142 and may abut the first end 146. The housing 136 may be attached to the lift arm 110 by coupling the second end 148 to the inner plate 114 of the lift arm 110.

The sliding structure 144 is configured to allow axial movement of the service pin 126 when the service pin 126 is rotated to a predefined rotational position to align the arm 130 with the sliding structure 144. The sliding structure 144 extends along entire length of the cylindrical portion 142 in direction parallel to the longitudinal axis 132. In the present embodiment, the sliding structure 144 is an opening extending in a direction parallel to the longitudinal axis 132. In another embodiment, the sliding structure 144 may be a groove, a slot, a dome or any structure generally known in the art which may allow the axial movement of the service pin 126.

The plate portion 150 may extend from an outer surface 152 of the cylindrical portion 142 in a direction perpendicular to the longitudinal axis 132. In the present embodiment, the first member 138 and the second member 140 are engaged with the plate portion 150.

The first member 138 is configured to engage with the second member 140 and the service pin 126 to selectively restrict the rotational movement of the service pin 126. The first member 138 may include a first end 154, a stopper 156, an engagement structure 158, and a pin 160. The first member 138 is pivotally attached to the housing 136. The first member 138 may be pivotally attached by attaching the first end 154 of the first member 138 to the plate portion 150. The first member 138 may include the stopper 156 at its other end. The stopper 156 may engage to the arm 130 of the service pin 126. In the present embodiment, the stopper 156 engages the groove 134. When engaged with the service pin 126, the stopper 156 prevents the rotational movement of the service pin 126. The stopper 156 may include but not limited to a hook structure, a protrusion, a pin or the like. In the present embodiment, the stopper 156 is a pin type structure.

The first member 138 may further include the engagement structure 158 configured to engage the second member 140. The engagement structure 158 engages the first member 138 with the second member 140 when the second member 138 is at the bottom position. The engagement structure 158 may be a protrusion, a hook, a pin or a similar structure known in the art. Furthermore, the pin 160 is configured to couple the first member 138 to the second member 140.

The second member 140 is slidably attached to the housing 136. In an embodiment, the second member 140 may be attached to the plate portion 150. The second member 140 is configured to slide between a bottom position and a top position with respect to the plate portion 150. In the bottom position, the second member 140 may retain the first member 138 engaged with the service pin 126. The second member 140 may include a straight portion 162 having a slot 164 and a lock structure 166. The slot 164 may extend along the length of the straight portion 162. The second member 140 may be engaged to the plate portion 150 by engaging the slot 164 with the plate portion 150 by using a bolt 168 such that the second member 140 is able to slide with respect to the plate portion 150. Further, the second member 140 may be engaged to the first member 138 by inserting the pin 160 in the slot 164. The slot 164 and the pin 160 may be configured to guide travel of the second member 140 between a bottom position (shown in FIG. 3) and a top position (shown in FIG. 5). The second member 140 may be moved from the bottom position to the top position to allow disengagement of the first member 138 from the service pin 126. Also, when the second member 140 is in the bottom position, the lock structure 166 engages the engagement structure 158 to restrict the pivoting motion of the first member 138 and thereby preventing the rotational movement of the service pin 126. In the present embodiment, the lock structure 166 is a bent portion with a slot and the engagement structure 158 is inserted in the slot to restrict the pivoting of the first member 138. Further, it may be appreciated that other configuration of the lock structure 166 such as a dome shape structure or a groove etc. generally known in the art may also be envisioned.

Referring to FIG. 5-8, the movement and positioning of various components of the service pin assembly 118 during unlocking of the service pin 126 is illustrated. As shown in FIG. 5, for unlatching the service pin 126, the second member 140 is moved upward from its bottom position. This allows disengagement of the engagement structure 158 from the lock structure 166 of the second member 140. Thereafter, the first member 138 is pivoted with respect to its first end 154. As shown in FIGS. 6 and 7, the pivoting of the first member 138 causes the disengagement of the stopper 156 thereby allowing the rotational motion of the service pin 126 about the longitudinal axis 132. After disengagement of the service pin 126 from the stopper 156, the service pin 126 is rotated in the cylindrical portion 142 such that arm 130 of the service pin 126 is aligned with the sliding structure 144 (as shown in FIG. 8). Once the arm 130 of the service pin 126 is aligned with the sliding structure 144, the second member 140 may be released from it top position. Once released, the second member 140 may come back to the bottom position due to gravity. Further, the service pin 126 may be moved axially through the cylindrical portion 142 into the lift arm 110 to engage a stationary frame with the lift arm 110. The engagement of the lift arm 110 to the stationary frame allows retention of the lift arm 110 in the raised position even if there is a leakage of fluid from the lift arm actuators 116 or a lever is actuated.

INDUSTRIAL APPLICABILITY

The present disclosure provides for the service pin assembly 118 for attachment to the lift arm 110 of the machine 100. The service pin assembly 118 includes the service pin 126 and the latch assembly 124. The latch assembly 124 when engaged with the service pin 126, retains the service pin 126 with the lift arm 110 in a disengaged position and restricts the axial and rotational movement of the service pin 126. The latch assembly 124 is configured to operate under gravity to lock or unlock the service pin 126 without using any tools.

During servicing of the machine 100, the lift arms 110 of the machine 100 are maintained in a raised position. An operator or a service personal raises the lift arms 110 to the desired height by operating a lever to extend the lift arm actuators 116. Once, the lift arms 110 are raised to the desired height and aligned with the stationary frame, the extension of the lift arm actuators 116 is stopped.

Now, the operator or service personal operates the latch assembly 124 to disengage the latch assembly 124 from the service pin 126. For disengaging the latch assembly 124, the second member 140 is moved to the top position by sliding it. As the second member 140 moves from the bottom position, the first member 138 is free to pivot about the first end 154. After moving the second member 140 from the bottom position, the service personal moves the first member 138. The movement of the first member 138 disengages the stopper 156 from the arm 130 and allows the rotation of the service pin 126 inside the cylindrical portion 142 of the housing 136.

The service pin 126 is rotated inside the cylindrical portion 142 to a rotation position such that the arm 130 of the service pin 126 is aligned with the sliding structure 144. Once, arm 130 is aligned with sliding structure 144, the second member 140 returns to the bottom position due to gravity. After aligning the arm 130 with sliding structure 144, the service pin 126 is pushed axially to couple the lift arm 110 to the stationary frame and thereby maintaining the lift arms 110 at the raised position during servicing. Therefore, the service pin 126 may be coupled with stationary frame without using any additional tools. Also, as all the components of the latch assembly 124 always remains coupled to the lift arm 110, the loss of the components is prevented. 

What is claimed is:
 1. A latch assembly for a service pin of a machine, comprising: a housing for rotatably receiving the service pin, the housing defining a sliding structure for axial movement of the service pin at a rotational position of the service pin; a first member pivotably attached to the housing and adapted to selectively prevent rotation of the service pin; and a second member slidably attached to the housing and movable to a bottom position to retain the first member.
 2. The latch assembly of claim 1, wherein the first member includes a stopper configured to engage the service pin.
 3. The latch assembly of claim 1, wherein the first member includes an engagement structure configured to engage the second member at the bottom position.
 4. The latch assembly of claim 1 wherein the first member comprises a pin to couple the first member to the second member.
 5. The latch assembly of claim 1, wherein the second member defines a slot to guide travel of the second member between a top position and the bottom position.
 6. The latch assembly of claim 1, wherein the second member includes a lock structure configured to engage the first member at the bottom position.
 7. The latch assembly of claim 1, wherein the sliding structure is an opening extending along a longitudinal axis of the housing.
 8. A service pin assembly for a machine, comprising: a service pin; a housing for rotatably receiving the service pin, the housing defining a sliding structure for axial movement of the service pin at a rotational position of the service pin; a first member pivotably attached to the housing and adapted to selectively prevent rotation of the service pin; and a second member slidably attached to the housing and movable to a bottom position to retain the first member.
 9. The service pin assembly of claim 8, wherein the service pin includes an arm configured to engage the first member.
 10. The service pin assembly of claim 8, wherein the arm is configured to align with the sliding structure to permit axial movement of the service pin.
 11. The service pin assembly of claim 8, wherein the sliding structure is an opening extending along a longitudinal axis of the housing.
 12. The service pin assembly of claim 8, wherein the first member includes a stopper configured to engage the service pin.
 13. The service pin assembly of claim 8, wherein the first member includes an engagement structure configured to engage the second member at the bottom position.
 14. The service pin assembly of claim 8, wherein the second member defines a slot to guide travel of the second member between a top position and the bottom position.
 15. The service pin assembly of claim 8, wherein the first member comprises a pin to couple the first member to the second member.
 16. The service pin assembly of claim 8, wherein the second member defines a slot to guide travel of the second member between a top position and the bottom position.
 17. The service pin assembly of claim 8, wherein the second member includes a lock structure configured to engage the first member at the bottom position.
 18. A machine, comprising: a lift arm; a service pin configured for insertion in the lift arm; a housing for rotatably receiving the service pin, the housing defining a sliding structure for axial movement of the service pin at a rotational position of the service pin; a first member pivotably attached to the housing and adapted to selectively prevent rotation of the service pin; and a second member slidably attached to the housing and movable to a bottom position to retain the first member.
 19. The machine of claim 18, wherein the housing is attached with the lift arm.
 20. The machine of claim 18, wherein the service pin is configured to engage the lift arm with a stationary frame during servicing of the machine. 